1. Field of the Invention
The invention relates to corrugated paper board manufacture and more specially relates to corrugator belt textile fabrics for the manufacturing of corrugator paper board on a corrugator machine.
2. Brief Description of the Prior Art
Corrugated paper board manufacture is described in U.S. Pat. No. 3,368,933. As described therein the corrugator belts employed to transport the web of corrugated board through the corrugator machine "should be strong and durable with good dimensional stability under the conditions of tension, high temperature, etc. encountered in the heating and cooling sections of the machine. The belts also must be comparatively flexible in the longitudinal or machine direction while retaining sufficient rigidity in the cross-machine direction to facilitate the guiding of the belts along their endless paths. In addition, the belts preferably should have sufficient porosity to permit the free transmission of vapor therethrough but at the same time should be sufficiently incompatible with moisture to avoid the adsorption of condensed vapor which might otherwise rewet the surfaces of the corrugated product.
In the U.S. Pat. No. 3,368,933 a corrugator belt is made from a perforated sheet of a polymeric resin. However, such belts do not perform well over wide ranges of operating temperatures, whereas textile fabric based belts do. The corrugator belts of the prior art made from textile fabrics have not always met the desired requirements of a corrugator belt in all respects. For example, the textile corrugator belts of the prior art are generally coarse weaves. They are relatively heavy fabrics and belts made therefrom are heavy belts requiring large amounts of power to drive them on the corrugator machines. The heavier prior art belts are also relatively inflexible and difficult to guide and track thorogh the corrugating machine. Further, the prior art corrugator belts generally have low permeabilities, i.e.; on the order of 4 to 10 CFM. At such low permeabilities, moisture passage is difficult if not impossible.
The textile fabric of our invention is flat woven and has all of the frictional surface characteristics desired for a corrugator belt fabric used in the manufacture of corrugator paper board on a corrugator machine.
The fabrics of the invention exhibit high permeability, i.e.; in the order of at least 10 and up to 2000 CFM. The retention or inhibition of vapor passage is minimal. Their light weight reduces power demands needed for driving belts made of the fabrics of the invention. The monofilament construction of belts made from fabric of the invention provides a diagonal mobility, aiding in their guidability on the corrugator machine.
Corrugator belts made from the fabric of the invention have also demonstrated increased drying rates for the corrugator machine, in operation. This is of course an economic advantage, reducing energy and steam requirements for a given production run. In addition, the fabric of the invention has the structural integrity required to join together the ends of the fabric in a conventional pin seam. Corrugator belts prepared from the embodiment fabrics of our invention combine the properties of an all monofilament belt including the ease of guiding, lightness, high permeability, superior strength, pin seam capabilities and having a smooth, non-marking, frictional surface (to avoid slippage between the belt and board).